Chapter 19: Blood Flashcards
The 2 main fractions of blood
plasma and formed elements
Plasma contains
water, plasma proteins, other solutes
Formed elements include
RBC, WBC, platelets, other solids
Plasma proteins
7%
-albumins, globulins, fibrinogen
Other solutes in plasma
1%
-specialized plasma proteins
Albumins
60%; produced in the liver; transport fatty acids and hormones
Globulins
35%; antibodies (immunoglobulins), transport globulins for hormones and steroids
Fibrinogen
4%; involved in blood clotting process, forming insoluble strands of fibrin from dissolved fibrinogen in serum
Other plasma proteins
1%; specialized proteins present at varying levels
ex: peptide hormones; insulin, follicle-stimulating hormones
Red Blood Cells
erythrocytes; contains hemoglobin which transports oxygen and carbon dioxide; provides red color
White Blood Cells
Leukocytes; component of the immune system
Platelets
cell fragments involved in clotting
Hemoglobin structure
complex quaternary structure with 4 globular protein subunits
Each Hb subunit contains
one molecule of heme
Each heme contains
one iron ion
Hemoglobin function
transports respiratory gases
Hemopoiesis
generates about 3 million new RBCs per second
-macrophages of the liver, spleen, and bone marrow monitor the RBC population and engulf RBCs before membranes rupture or hemolyze
Blood Typing
determined by presence or absence of A, B, and Rh antigens
4 basic surface antigens and plasma antibodies
- A; antigen A; B antibodies
- B; antigen B; A antibodies
- AB; antigens A and B; no antibodies
- O; no antigens; both A and B antibodies
Coagulation phase
blood clotting begins 30 seconds after injury
-chain reactions convert circulating fibrinogen into insoluble fibrin
Pathways of coagulation phase
extrinsic, intrinsic, common
Extrinsic pathway
-begins in vessel wall, outside bloodstream
-damaged tissue cells release tissue factor (TF)
-TF and other factors form an enzyme complex that activates Factor X
Intrinsic pathway
-begins with circulating proenzymes, within bloodstream
-enzymes activated by collagen
-series of reactions activates Factor X
Common pathway
-convergence of extrinsic and intrinsic pathways to activate Factor X
-enzymes form the prothrombin activator complex that converts prothrombin to thrombin
-thrombin converts fibrinogen to fibrin
